/Engine/Source/Editor/GraphEditor/Public/GraphActionNode.h
Takes the tree view and expands its elements for each child.
void ExpandAllChildren ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [STreeView](API\Editor\UnrealEd\STreeView)< [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FGraphActionNode](API\Editor\GraphEditor\FGraphActionNode) > > > TreeView, bool bRecursive )